Label stripping apparatus for use with label handling apparatus

ABSTRACT

A label stripping apparatus including first and second guide members extending parallel to one another from a support member which is mounted for rotation between first and second positions about an axis coincident with the axis of the second guide member. The apparatus also has a label stock comprising a plurality of labels positioned along a strip of label stock backing, wherein the label stock extends between the guide members under tension when the support member is in the first position. When the support member is rotated to the second position, the first guide member moves the label stock into contact with the second guide member causing the label stock to distort around the second guide member. This distortion separates at least a portion of a label adjacent the second guide member.

United States Patent 1191 Real 1 1 LABEL STRIPPING APPARATUS FOR USE WITH LABEL HANDLING APPARATUS 175] Inventor: Kenneth A. Real, Redmond. Wash.

[73] Assignee: Interface Mechanisms, lnc.,

Mountlake Terrace, Wash.

221 Filed: on. 3, 1973 [21] Appl. No.: 403,278

[52] U.S. Cl. 221/73; 156/541; 156/584 [51] Int. Cl. B65C 9/18 [58] Field of Search 221/70-73; 156/584, 384, 540, 541

[ 56] References Cited UNITED STATES PATENTS 2,419,809 4/1947 Avery 156/584 X 3,222,242 12/1965 lngalls et al.... 156/584 3,403,066 9/1968 lkelheimer 221/73 X 3,556,898 1/1971 Allen r r 221/73 X 3,619,326 11/1971 Burbidge 221/73 X 3,654,016 4/1972 Alexander... 156/584 X 3.741.847 6/1973 Sato 156/541 X FOREIGN PATENTS OR APPLICATIONS 671.040 9/1963 Canada. 221/73 Dec. 2, 1975 Primary ExaminerRobert B. Reeves Assistant ExaminerCharles A. Marmor Attorney, Agent, or Firm-Christensen. OConnor. Garrison & Havelka [57] ABSTRACT A label stripping apparatus including first and second guide members extending parallel to one another from a support member which is mounted for rotation between first and second positions about an axis coincident with the axis of the second guide member. The apparatus also has a label stock comprising a plurality of labels positioned along a strip of label stock backing, wherein the label stock extends between the guide members under tension when the support member is in the first position. When the support member is rotated to the second position, the first guide member moves the label stock into contact with the second guide member causing the label stock to distort around the second-guide member. This distortion separates-at least a portion of a label adjacent the second guide member.

2 Claims, 11 Drawing Figures US. Patent Dec. 2, 1975 Sheet 1 of3 3 ,923,199

US. Patent Dec. 2, 1975 Sheet20f3 3,923,199

LABEL STRIPPING APPARATUS FOR USE WITH LABEL HANDLING APPARATUS BACKGROUND OF THE INVENTION This invention relates generally to printing devices, and more specifically, to the art of high speed mechanical impact printers.

Mechanical impact printers are generally well-known in the art, although frequently such printers must be specially adapted for particular applications. The printing of bar codes, such as that disclosed in US. Pat. No. 3,700,858 to Murthy, for purposes of high speed item identification, requires high resolution, accurately spaced, printing. The individual characters must be clear and precise, and the separation between characters accurate and uniform. If such high resolution, uniform printing is not maintained, errors in reading the bar code will increase, to the detriment of the identification system using the code.

Furthermore, in the printing of label stock, the operator of prior art printers must peel off the individual labels manually from the stock backing after they are printed in order to affix them to the commercial item; e.g., carton, which is to be identified. This manual stripping of the labels from the stock backing is often impractical as it can only be accomplished some distance away from the rotating printing element.

Thus, there is a current need in particular printing applications for an impact printer, otherwise utilizing conventional impact printing principles, which is capable of printing high resolution, accurately spaced, characters for particular code printing applications, and in the case of label stock, for a means which presents the labels to the operator after printing in a condition such that they may be readily stripped and affixed to the item to be identified. In accordance with the above, it is a general object of the present invention to provide a mechanical impact printer which overcomes the disadvantages of the prior art.

It is another object of the present invention to provide an impact printer wherein the printing stock supply reel has a tensioning means in conjunction therewith for maintaining a substantially constant tension on the printing stock.

It is a further object of the present invention to provide an impact printer in which the time for actuation of the print hammer is substantially decreased.

It is yet another object of the present invention to provide a mechanical impact printer having a print wheel which is rotated by means of a compressible ring connection between the driving means and the print wheel.

It is a still further object of the present invention to provide a mechanical impact printer wherein labels may be individually stripped immediately after printing is accomplished.

SUMMARY OF THE INVENTION According, a label stripping apparatus is provided which includes a label stock guide having two upright members, between which label stock is free to flow under tension, and means for moving one of the upright members relative to the flow of label stock such that the label stock is forced to follow a severe bend around the other upright member. In attempting to follow this now distorted path, the labels separate from the stock back.

DESCRIPTION OF THE DRAWINGS A more thorough understanding of the invention may be obtained by a study of the following description of the preferred embodiment taken in connection with the accompanying drawings in which:

FIG. 1 is a simplified isometric view of the impact printer.

FIG. 2 is an elevation view of the label stripper mechanism of the present invention.

FIG. 3 is a plan view of the label stripper mechanism of the present invention.

FIG. 4 is an isometric view of the tensioning means associated with the stock supply reel of the present invention.

FIG. 5 is a partial section elevation view of the print hammer actuator mechanism of the present invention.

FIG. 6 is a section view of the print wheel of the present invention.

FIG. 7 is a simplified representation of the print hammer actuator mechanism of the present invention.

FIG. 8 is a graph of the motion of the print hammer against time during actuation.

FIG. 9 is a graph of the current through the coil of the print hammer actuator mechanism of FIG. 7 against time during actuator.

FIG. 10 is a top plan view of the compressible pad of the present invention.

FIG. 10a is a section view of the compressible pad, taken along lines 10a10a in FIG. 10.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. I, an isometric view of the impact printer of the present invention is shown. As in prior art printers, input power is supplied via a standard volt line (not shown) to a power supply module 12, which in turn provides power for the printer, including the logic control circuit 14. Signals from peripheral equipment can be connected into the printer through connector 16 to the motor drive circuit 18, and the logic control circuit 14. These two circuits control, in conventional fashion, the operation of the printer. Printing stock 19 is typically stored on a supply reel 20, and is directed around arm 22, through stock sensor 24, through a print station, comprised of print hammer assembly 26 and a cylindrical print wheel 28, through a label stripper 30, and then through a stock stepper assembly 32, which typically contains a motor drive and a pair of rollers, for placing the printing stock under tension.

The ink ribbon 34 is typically stored on a supply reel 36, first positioned partially around guide pin 38, then directed between the printing stock 19 and the circumferential surface of the print wheel 28 before going through a powered ribbon drive assembly 40, and finally wound up on a ribbon take-up reel 42 which is driven by motor 44. The print wheel 28 is continuously rotated in operation by means of drive motor 46 acting through a drive wheel 54 and belt 48.

In operation, print wheel 28, having a set of raised print characters arranged around its circumferential surface, continuously rotates by means of drive motor 46, and the ribbon 34 and printing stock 19 are pulled past the print station comprising print hammer assembly 26 and print wheel 28 by means of their respective take-up motors. The logic control board 14 issues signals commands to the print hammer assembly 26, which signal commands actuate the print hammer to impact the printing stock 19 and the ribbon 34 sufficiently against the circumferential surface of the print wheel 28 that a single raised character is imprinted on the stock 19. A system for synchronizing the operation of the rotating print wheel and the hammer assembly is disclosed in copending application Ser. No. 110,517, filed Jan. 28, l97l, entitled High Speed Printer and is assigned to the same assignee as the present invention. Briefly, such a synchronization system utilizes a cylindrical code wheel, attached to the print wheel and rotating therewith, which code wheel has a plurality of coded holes patterns, one for each print character, located therein. Photoelectric means is used to detect the hole patterns, which data is in turn applied to a circuit which compares the code data with signals representing the desired character selected at a keyboard or similar device. When there is a coincidence, the print hammer is actuated, resulting in the desired character being printed.

Referring now to FIG. 6, a cross section view of the print wheel assembly of the present invention is shown. The print wheel assembly consists generally of: a housing 52, which is attached to the deck of the printer; a drive assembly comprising drive wheel 54, bearing 56 and drive shaft 58; print wheel 60; securing knob 62; and a compressible plastic ring pad 64. In operation, motor 46 (FIG. 1) rotates drive wheel 54 by means of the belt 48 (FIG. 1) connecting the motor 46 and the drive wheel 54. Shaft 58 does not rotate with the drive wheel 54, but is anchored into the housing 54 by end bolt 57.

The print wheel 60 is secured to the rotating drive wheel 54 by means of the compressible ring pad 64, which is positioned between the drive wheel 54 and print wheel 60. The print wheel 60 is forced toward the drive wheel, compressing ring pad 64, by means of screw-adjusted securing knob 62, which is turned into the drive shaft 58. Thus, the only contact between drive wheel 54 and the print wheel 60 is through the compressible polyurethane ring pad 64, shown in position in FIG. 4, and in more detail in FIGS. and 10a. The compressible pad 64 is in the shape of a ring having outer and inner boundary surfaces 65 and 67, respectively. A trough 68, formed in the ring pad 64 enables the ring pad to be fitted snugly over a mating ring 69 in drive wheel 54. Trough 68 substantially follows the shape of the outer and inner boundary surfaces 65 and 67, resulting in a compressible ring pad having two concentric edge members 64a and 64b extending perpendicularly from a cross member 640 connecting edge member 64a and 64b and one end thereof. Extending away from surface 64d of connecting member 64c are a plurality of integral compressible hemispheres 7070, which are of the same compressible polyurethane material as the remainder of the compressible ring pad.

Print wheel 60 rests on the plurality of compressible hemispheres 70-70, and these hemispheres are compressed by the action of tightening securing knob 62 into shaft 58. The friction fit between the print wheel 60, the compressible ring pad 64 and the ring portion 69 of drive wheel 54 is sufficient to rotate print wheel 60 by rotating drive wheel 54 by means of motor 46 and belt 48, without slippage between them. A bearing 66 is positioned between the print wheel 60 and shaft 58 to provide rotational freedom of movement. The friction drive of print wheel 60 accomplished by compressible ring pad 64 eliminates the need for high tolerance machining and keying to mate a print wheel with a drive wheel, as is done in the prior art. The friction drive also significantly reduces the potential for printing inaccuracies due to wear or poor machining of the print wheel 60 or the drive wheel 54. Furthermore, such an arrangement allows for the print wheel to be easily removed for cleaning or exchange, as desired, without the necessity of time-consuming realignment of the printing wheel assembly.

The print station, as mentioned above, comprises print wheel assembly 28 and the print hammer assembly 26 (FIG. 1) which is under the control of control logic circuit 14. Referring to FIG. 5, the print hammer assembly 71 is shown in a partial section view. When the hammer is to be actuated toward print wheel 72, a signal is applied from control logic 14 (not shown) to an electromagnet (not shown) within the assembly. When the electromagnet is energized by current flowing through its coil (not shown) lever arm 74 which is secured to the hammer assembly 71 by flexible member 76 at one end thereof, is drawn into contact with a portion 78 of the assembly electromagnet (otherwise not shown). As lever arm 74 moves toward the magnet portion 78, hammer arm 80 moves in the direction of the arrow toward the circumferential surface 73 of print wheel 72. At the other end 83 of hammer arm 80 is connected hammer 70. When lever arm 74 is actuated, hammer 70 moves in the direction of the arrow toward circumferential surface 73 of print wheel 72 to such an extent as to impact the printing stock (not shown) and ink ribbon (not shown) positioned between the print wheel 72 and the print hammer 71 against a particular character 72a on circumferential surface 73.

When the current is discontinued through the electromagnet, lever arm 74 springs back away from engagement with magnet portion 78 by means of flexible member 76. The force of this spring-back is absorbed by spring loaded stop 84, and any oscillations of hammer arm 80 are quickly damped. Such a print hammer assembly is commonly referred to as a cantilever beam assembly.

A principal disadvantage to such print hammer assemblies has been the time heretofore required to actuate and retrieve the print hammer mechanism. The response time of the mechanism is dependent on the rate of increase of current or di/dt, in the electromagnet coil. The greater the rate of increase in current over time, the faster the hammer will actuate. Heretofore, however, coil di/dt has been limited because high di/dt values have been obtained only by using actuator circuits which produce a high value of coil current for much of the hammer travel time, which results in undesirable coil heating and drive transistor strain, ultimately resulting in failure of both elements.

To prevent high heat loss and coil failure, while significantly increasing coil di/dt so as to provide faster actuation of the print hammer, the actuator circuit of the present invention has been developed. Referring to FIG. 7, a significantly higher actuating voltage V, than is provided by the prior art lOO volts as opposed to approximately 25 volts) is connected through a transistor and an RC circuit comprising capacitor 92 and resistor 94 to the electromagnet coil 96. Transistor 90 is controlled by a signal from control logic circuit 14 (not shown). In operation, when transistor 90 is turned on by the logic control signal, current flows primarily through capacitor 92 and coil 96. A diagram of coil current i time is'shown in FIG. 9. As the charge on capacitor 92 approaches actuating voltage V the current decreases to avalue dependent on-resistor 94, thus limiting-the energy dissipated 'in coil;9.6.to atolerable level and easing the load on transistor. 90. Because of the high initial rate of current increase, however, the hammer 97 begins to move substantially sooner than previously, .and actuation time is reduced. At 1.2 milliseconds from the start of current flow, hammer 97 impacts the paper stock and ribbon against the desired character 99. A graph of distance v. time "for' the travel of the print hammer is shown in FIG. 8.

Referring again to FIG. 1, printing stock 19 is directed through a print station comprising print hammer assembly 26 and print wheel 28 by means of a supply reel 20, and a label stepper 32, which exerts a pulling force on stock 19. However, in certain applications, such as label printing, where the movement of the printing stock is not uniform, slack will tend to occur in the printing stock between the supply reel and the print station. Any such slack is ordinarily unsatisfactory, as it results in either distortion of the printed characters or variations in the character separation or both. The printed code is thus more difficult to accurately read and subject to an increased number of reading errors.

To overcome this tendency, a tensioning means is provided by the present invention in conjunction with the supply reel 20, as shown in FIG. 4. A printing stock supply reel 100 is positioned conventionally ona reel spindle 102. In operation, stepper 32 exerts a pulling force on stock 19, and hence pressure on roller guide 104, which roller guide is rotatably mounted on one end 105 of guide arm 106. The other end 107 of guide arm 106 is fixedly connected to a rotating arm assembly 108, which comprises a cylinder 110 fixedly mounted on plate 112, which arm assembly rotates with the rotation of guide arm 106 about a fixed central shaft 114 against the tension of spring 1 16, one end of -FIGS. 2 and 3. In operation, the label stock (when which is secured to a fixed peg 118, and the other end I to a peg 120 on the rotating arm assembly 108. As the force on stock 101 increases in the direction of the arrow, thus forcing guide arm 106 to move counterclockwise about central shaft 1 14, the rotating arm assembly 108 also rotates counterclockwise, forcing the free end 122 of pivot arm 124 toward the periphery of supply reel 100 against the tension of spring 126. This movement of pivot arm 124 reduces the braking force of tension arm 126, which is secured to pivot arm 124, against supply reel spindle ring 128, allowing spindle 102 to rotate more freely, and thus feed printing stock 101 faster. Roller guide 104 and guide arm 106 will eventually reach an equilibrium angular position when a constant force is exerted on stock 101. However, if the force on stock 101 varies, as in label printing, the angular position of guide 104 and guide arm 106, and hence, the remainder of the system will attempt to track the force, searching for an equilibrium posi tion.

For instance, if the force on roller guide 104 is suddenly reduced, as would occur with the return of the stripper to its original position, the tension exerted by spring 116 will tend to rotate the arm assembly 108 in the clockwise direction, and along with it guide arm 106 and roller guide 104 until a system equilibrium is the braking force on spindle ring 128 exerted by tension arm=126, and the supply reel will thus be increasingly braked. Sucha responsive tensioning devicetends to'maintain that portion of printing stock 101. located between the supply reel and the print station in substantially constant tension, thus increasing printing resolution and accuracy, and hence, reducing code reading errors. i

Following the print station-islocated a label stripper 30, shown generally in FIG. '1 and inmore detail in used) is passed between guide'elements- 130 and 132, connected by support member 133. The entire stripper 30 is rotatable about axis 134,134 with respect to the deck of the printer, so that it may be conveniently taken out of operation. Guide elements 130 and 132, as well as support element 133 are rotatable about axis 135135. By rotating the stripper about axis 135-135 in a clockwise manner from its original position by convenient means of rotation knob 142, peg 130 guides the label stock through a substantially U- shaped path before it comes to the label stepper 32. Although the stock backing follows such a path, the labels 21- themselves do not, and separate from the backing when the backing begins to bend to follow the U- shaped path. By thus rotating label stripper knob 142 in such a fashion, the operator is able to strip a label in close proximity to the print mechanism, and then conveniently place them, if desired, on appropriate cartons or other commercial items. Located within rotation knob 142 is a spring 140, which is secured at one end thereof such that the knob, and hence, guide pins 130, 132 are rotated against the tension of the spring. When the knob 142 is released, the action of spring 138 returns the stripper elements to their rest position of FIG. 1. Bendable stop 141 is provided to lock the stripper in operating position, if desired. A spring 138 is positioned so as to place the stripper 30 and element 139 in tension along shaft 139a.

Thus, a mechanical high speed impact printer has been disclosed which utilizes a generally conventional configuration but which has several novel features to increase printing resolution, printing accuracy, and operational convenience in the printing of bar codes on labels or other printing stock.

Although an exemplary embodiment of the invention has been disclosed herein for purposes of illustration, it will be understood that various changes, modifications and substitutions may be incorporated in such embodiment without departing from the spirit of the invention as defined by the claims which follow.

What is claimed is:

1. A label stripping apparatus for use with a label handling apparatus including a base plate and means mounted on the base plate for moving, under tension along a first path, label stock comprising a plurality of labels positioned along a strip of label stock backing, said label stripping apparatus comprising:

a. a label stock guide means including a support member and first and second guide members, said first and second guide members being spaced apart from each other on said support member and extending in a substantially parallel direction to each other from said support member, said second guide member having a longitudinal axis aligned with said substantially parallel direction,

b. means mounting said label stock guide means on the base plate for rotation about an axis coincident with said longitudinal axis of said second guide member between first and second positions so that said first and second guide members are transverse to the first path of the label stock, and positioning said label stock guide means with respect to the first path so that the label stock extends along said first path between said first and second guide members when said label stock guide means is in said first postion, and the label stock is moved away from said first path when said label stock guide means is rotated to said second position wherein said first guide member moves the label stock into 10 further including means for locking said label stock guide means in said second position. 

1. A label stripping apparatus for use with a label handling apparatus including a base plate and means mounted on the base plate for moving, under tension along a first path, label stock comprising a plurality of labels positioned along a strip of label stock backing, said label stripping apparatus comprising: a. a label stock guide means including a support member and first and second guide members, said first and second guide members being spaced apart from each other on said support member and extending in a substantially parallel direction to each other from said support member, said second guide member having a longitudinal axis aligned with said substantially parallel direction, b. means mounting said label stock guide means on the base plate for rotation about an axis coincident with said longitudinal axis of said second guide member between first and second positions so that said first and second guide members are transverse to the first path of the label stock, and positioning said label stock guide means with respect to the first path so that the label stock extends along said first path between said first and second guide members when said label stock guide means is in said first postion, and the label stock is moved away from said first path when said label stock guide means is rotated to said second position wherein said first guide member moves the label stock into contact with the second guide member to distort the label stock about said second guide member to separate at least a portion of a label adjacent said second guide member from the label stock backing, and, c. means for moving said label stock guide member between said first and said second positions.
 2. The label stripping apparatus as recited in claim 1, further including means for locking said label stock guide means in said second position. 